An undated photo of a mirabilis triflora plant, one of the 50 “lost” species found by San Diego Natural History Museum botany curator Jon Rebman.

It’s been more than 120 years since botanists have seen some flowers, ferns and shrubs in Baja California Sur. They’re called “lost plants,” with scientists in possession of only a handful of old specimens.

Scientists may not have been actively looking for the plants all this time, but they still never came across them in more than a century, according to Jon Rebman, botany curator for the San Diego Natural History Museum. So last year, Rebman spent 10 months in Baja California Sur on the hunt for these rare species to see whether some had gone extinct.

“Extinction is a really hard thing to say because some of these species require winter rainfall which is really rare in that part of the peninsula,” Rebman said. “If they get enough, the plants can pop up on these big plains. You could look for years, but unless it’s the right conditions, they’re not even going to show their heads.”

Rebman said last year it rained more than it normally does and he found 50 lost plants, traveling to remote areas and through abandoned, overgrown paths. The finding is significant even if these plants don’t have any immediate applications in medicine or other fields.

“I hate that aspect, that it has to be something that we value (in order to be worthwhile),” Rebman said. “But it’s a part of a healthy ecosystem. To me, it’s like we’ve inherited this rich heritage of biodiversity. You don’t want something to blink out on your watch. Now we know at least 50 are there and the threats to them.”

Rebman will be presenting some of his findings at theNAT Tuesday at 7 p.m. He joins KPBS Midday Edition on Monday with more on how areas of the the Baja California Peninsula has changed since botanists last visited.